It's Manchester United's youth against AC Milan's experience in the first leg of their UEFA Champions League semifinal series on Thursday

United is led by the Professional Footballer's Association Player of the Year Cristiano Ronaldo, 22, and Wayne Rooney, 21. AC Milan will counter with a defense that includes Paolo Maldini, who is 38, and Alessandro Nesta, 31. Seven projected Milan starters played in the 2003 final when Milan won its last Champions League title.

With his team depleted by injuries -- out are eight first-team players, including defender Rio Ferdinand and midfielder Kieran Richardson, who were injured in Saturday's 1-1 draw with Middlesbrough -- Manchester United manager Sir Alex Ferguson says the experience is critical at this stage of the competition.

"You can't deny that kind of experience," Ferguson said of AC Milan's core of veterans. "Sometimes I look at my own team and I wish we maybe sometimes had more experience in certain situations. But then sometimes I get encouraged by the hope and the future of the younger players who can really excite people. It's a difficult one. Maldini leaves a legacy. Young players like Rooney and Ronaldo give you a future, but it's very difficult to say what's best at this moment in time."